Blue light emission from ZnSe p-n junctions

Abstract

Pure blue light emission has been obtained from ZnSe p-n junctions. ZnSe crystals are grown by the temperature difference solution growth method under controlled vapor pressure. A p-type ZnSe crystal can be grown from Se solution by doping with a group I element under controlled Zn pressure. The properties of p-type crystals have been measured by the van der Pauw method. A p-n junction has been made by the formation of the n-type layer by Ga diffusion into the p-type crystal. The fundamental properties of the p-n junctions are as follows: the value of n in the I-V characteristics ranges from 1.4 to 1.8 and the diffusion potential is between 2.5 and 2.7 eV. The emission spectrum from the p-n junction depends on the vapor pressure during growth and blue light emission is obtained with optimum pressure. The wavelength of the main emission peak is 460 nm at 77 °K and 480 nm at 300 °K. The brightness is 2 mcd at 2 mA.